Overview

Geometry is the branch of mathematics concerned with the properties of and relationships between points, lines, planes, angles, and solids and with generalizations of these concepts.

If geometry has always been your nemesis, here we will explain simply and easily how to do every kind of geometrical problem you are likely to face in the performance of your professional job or study of mathematics in a high school or college, from angles to solid bodies.

This section contains the most frequently used formulas, rules, and definitions regarding to the following:

1. Angles

2. Areas

3. Solid Bodies

1 Definition of an Angle

Two rays that share the same endpoint form an angle. The point where the rays intersect is called the vertex of the angle. The two rays are called the sides of the angle.

2 Unit Measurement of Angles

The radian measure of the angle ? is the ratio of the arc length to the radius.

1 radian = 57.2957 ⁰

3 Acute Angles

An acute angle is an angle measuring between 0 and 90 degrees.

4 Obtuse Angles

An obtuse angle is an angle measuring between 90 and 180 degrees.

5 Right Angles

A right angle is an angle measuring exactly 90 degrees.

6 Complementary Angles

Two angles are called complementary angles if the sum of their degree measurements equals 90 degrees.

7 Supplementary Angles

Two angles are called supplementary angles if the sum of their degree measurements equals 180 degrees.

8 Vertical Angles

For any two...